The proposed research has several aims. A major study assesse plasma free-androgen level differences between handedness, sex, and familial sinistrality (FS) groups. In addition, it seeks to determine the relationship between androgen levels and language laterality and ability characteristics we have found to vary with handedness, sex, and familial sinistrality. A specific hypothesis regarding androgen levels in right handers will be tested. The hypothesis is that androgen levels are lower in those Ss having a positive family history of left handedness. The hypothesis suggests that FS+ females are less "androgynous" than FS- females and FS+ males are more "androgynous" than FS- males. Other studies are concerned with testing hypotheses about language lateralization assessed by innocuous behavioral tasks and with achieving a better understanding of such tasks. A new auditory task, analogous to the visual Object Naming Latency Task, will be devised to allow the determination of whether or not a common nonmodality specific naming process can be demonstrated. Another study tests the hypothesis that the Navajo, because of their language and "appositional" outlook, will show left rather than the typical right ear superiority on a verbal dichotic task. Another study devises new tasks to assess laterality differences between handedness, sex, and FS groups in "associative naming". Two studies are designed to answer questions about the susceptibility of laterality tasks to error induced by S knowledge of Experimenter interests and expectations. All in all, the proposed studies, which follow from our previous findings, have the potential for substantially increasing our understanding of important aspects of language lateralization and of ability patterns in normal persons.